Rent The Runway: HELP ME

So, here's the deal people:  I am in the {2nd} Royal Wedding later this year, but the first of many parties for this event is in March.  The engagement party!  Do I have dresses for this kind of shindig?  Of course, but then I got a [birthday] email from the ladies at RTR giving me $50 off my next rental.  On numerous occasions I've had multiple dresses in my cart, ready to check out, but I've never actually pulled the trigger.  I think it will be fun to rent a dress for this event [especially since it'll cost me around $30, as opposed to the norm that runs closer to $100 after all the add-on fees].  BUT now I need y'alls help because I can't decide which one to rent!  HELP ME HELP ME PLEASE!!  Here are the choices:


Shoshanna Lace Boatneck Back Dress

 Milly Sophia Lace Shift

 Kate Spade Nantucket Party Dress

 Robert Rodriguez Collection Peony Lace Shift

 Milly Sweet Madeline Dress

 Milly Stepford Wife Dress

 Shoshanna It's My Birthday Dress

photos via RTR